Practical Approaches to Hot-Mix Asphalt Mix Design and Production Qualifty Control Testing. Transportation Research Circular E-C124

摘要

Since the introduction of the Superpave mix design procedure, there has been considerable research to refine the design procedure so that laboratory tests and procedures used during the hot-mix asphalt (HMA) mix design process relate better to actual field performance. Also, a number of agencies have been concerned with the lack of a proof test for validating the volumetric properties. Many have expressed a desire for a truly simple mix test that could be employed at the HMA plant lab level. These issues were explored in a workshop at the 85th Annual Meeting of the Transportation Research Board (TRB). The papers in this document were written following the workshop and are based on the presentations; the papers have not undergone a formal peer review. The first paper offers a state-of-the-practice for Superpave mix design and specification, which is based on an in-depth survey of the regional UserProducer Groups. It includes a summary of changes made to the Superpave mix design procedure as a result of NCHRP research findings, Expert Task Group/American Association of State Highway and Transportation Officials (ETG/AASHTO) recommendations, and individual state experience. The remaining papers deal with other tools for mix design and evaluating HMA during production that are relatively simple and implementable. This includes such things as the Bailey method of gradation evaluation, use of the Superpave gyratory compactor to assess performance, and use of the locking point to establish NDesign. In addition, other mix tests that show some potential as practical tools for use in the verification of mix designs and the quality control of HMA production are offered. These changes and new tools are intended to improve the field performance of HMA.